As discussed in Lustre bugzilla 22435 dynlocks are provided by the ldiskfs and are not a generic facility. They should be removed from the mdd-level to allow building --without-ldiskfs per Andreas's comment in 22435:

https://bugzilla.lustre.org/show_bug.cgi?id=22435#c3

This change converts the instances of "struct dynlock_handle *" to a "void *" pointer which is safe because they are never dereferenced at this level.

It also wraps the "struct dynlock" entry in the mdd_object with MDD_DISABLE_PDO_LOCK. This effectively limits all direct dynlock usage to the !MDD_DISABLE_PDO_LOCK case which is unconditionally disabled in the code. Presumable this code will simply be removed at some point which will fully resolve the issue.